First, we show how to perform cDFT, i.e. SCF calculation of excited state, of formaldimine molecule CH2=NH. CH2=NH has in total 12 electron, from them 6 are double occupied molecular orbitals. Here we will run cDFT with a single excitation moving one electron from HOMO to LUMO state. The cDFT calculation is initiated by keywords icdft = 1. See example of fireball.in file.

-

Here is input file with initial geometry {{:​scfe:​CNH3.bas|}}.

-

{{:​scfe:​cnh3-w.png?​400x200}}

-

fireball.in

-

<​code>​

-

&OPTION

-

basisfile = CNH3.bas ​

-

icluster = 1

-

nstepf = 1

-

T_initial = 100.0

-

T_final = 100.0

-

sigmatol = 0.000000001

-

dt = 0.01

-

iquench = 0

-

max_scf_iterations = 200

-

icdft = 1

-

&END

-

-

&OUTPUT

-

iwrteigen = 1

-

iwrtxyz = 1

-

&END

-

-

&MESH

-

&END

-

-

</​code>​

-

-

To move electron from one orbital to another we need to create elh.inp input file in a directory. The first line means how many electrons is in the system. The first position of the second line means number of orbital where we want to create a hole. The second position determines occupancy of the hole (between 0-1). In this case there is missing one electron in HOMO orbital. The third line first position tells where is placed excited electron, the second position means how much electron you excite. ​ ​Fig.1 ​

-

<​code>​

-

12 ! total number of electron

-

6 0.5 ! unocculied state

-

7 0.5 ! occupied state

-

</​code>​

-

Results of such calculation is on the fig[1]

-

-

====== Example 2 ======

-

There is also possible to perform quenching of the excited state. The example is shown on the above mentioned system. CH2=N2 molecule can be found in two symetric conformations (Hydrogen bounded on N is in left or on the right side). Such transition is carried out by excitation of one electron from Homo to Lumo. Transition from one conformation to another pass through the conical intersection which is the local minimum of the excited state. In this example we will optimize geometry to the conical intersection. We only switch on keyword iquench = 1 and let them relax. Example of fireball in is below and elh.in file is the same as above: